hitunglah:a.luas diarsir b.keliling diarsir

A.luas yang diarsir
  a)1/2×1/2 ×π×r²
     1/2×1/2×3,14×4×4
      =12,56cm²
  b)1/2×1/2×π×r²
     1/2×1/2×3,14×3×3
     =7,65cm²
  c)12,56cm²+7,65cm²
     =20,21cm²
B.keliling yang diarsir
   a)K=π×d
      K=1/2×1/2×π×d
        =1/2×1/2×3,14×8
        =6,28cm
   b)K=π×d
      K=1/2×1/2×3,14×6
        =4,71cm
   c)6,28cm+4,71cm
      =10,99cm
maaf kalo salah:)
semoga membantu..